In recent years, liquid crystal display panels which have advantages such as thin thickness, light weight, low-voltage drive, and lower power consumption have been widely used as display panels for various electronic apparatuses such as mobile terminals (e.g., mobile telephones and mobile game machines) and notebook personal computers.
In the field of displays, in recent years, considerable attention has been directed to display panels which include a plastic substrate having great advantages over glass substrates in terms of flexibility, shock resistance, and light weight, and to potential novel display panels which could not be produced using a glass substrate.
As such a display panel, for example, a liquid crystal display panel which includes a pair of substrates (i.e., a thin film transistor (TFT) substrate and a color filter (CF) substrate) and a liquid crystal layer provided between the pair of substrates, and in which each of the TFT substrate and the CF substrate has a flexible plastic substrate made, for example, of a translucent resin material, has been suggested.
Here, in fabricating a liquid crystal display panel, the liquid crystal display panel needs to be provided with a terminal to be connected to e.g., an integrated circuit chip (or an IC chip), which is an electronic component, and a picture-frame region (i.e., a terminal region) where the terminal is provided needs to be exposed. In this case, unwanted portions of one of the pair of substrates, i.e., the CF substrate and the TFT substrate, (e.g., the CF substrate if the terminal is provided on the TFT substrate) need to be cut off.
As a cutting technique for exposing the terminal region of the liquid crystal display panel including a plastic substrate, techniques such as cutting by a dicing saw, or punching using a cutting die has been used.
However, in these techniques, accurate height positioning of the saw and the stage, and flatness are required so that the CF substrate is completely cut off without causing any damage to a wire electrode on the TFT substrate. Thus, it is difficult to increase size and production scale.
As a substitute for these techniques, a technique of cutting the plastic substrate by irradiation with laser light has been suggested. The cutting technique by irradiation with laser light has been proved to be capable of cutting one layer of the plastic substrate, and cutting the TFT substrate and the CF substrate at the same points when the two substrates are bonded together as a bonded body, due to optimization of conditions of the laser light irradiation.
However, as mentioned above, the plastic substrate is made of a translucent resin material, and therefore, in cutting a portion of the CF substrate which corresponds to the terminal region by irradiation with laser light, the wire electrode in the terminal region on the TFT substrate may be irradiated with the laser light, which may result in causing damage to the wire electrode and breaking the wire.
In view of this problem, a method for preventing the breakage of the wire due to irradiation with laser light has been suggested. More specifically, as a liquid crystal display panel having a TFT substrate including a terminal region in which a terminal and a wire are provided, and a CF substrate facing the TFT substrate, a liquid crystal display panel in which a metal layer for reflecting laser light is provided on an inner surface of the CF substrate which faces the terminal region has been suggested. It is described in Patent Document 1, for example, that with this configuration, it is possible to reduce damage to the terminal region due to irradiation with laser light, and improve the quality and reliability of the liquid crystal display panel.